A goiter is a swelling of the thyroid gland in the neck. It can be caused by an overactive or underactive thyroid. Goiters are more common in women, older people, and those from areas without iodized salt. Small goiters may disappear on their own but large goiters can press on the trachea and cause breathing problems. Treatment options include thyroid medication, surgery to remove parts of the thyroid, or removal of the entire thyroid gland. Preventing iodine deficiency through iodized salt can help prevent endemic goiters.